1. Field of the Invention
The present invention relates to an air bag device for extending an air bag at the time of a collision of a vehicle to protect an occupant and, particularly, to a device to be mounted in a steering unit and suited as an air bag device for a driver. More particularly, the present invention relates to an air bag device which is improved to have the air bag extended quickly.
2. Description of the Related Art
The air bag device to be mounted in a stationary portion in front of a seat of a vehicle is intended to protect an occupant in an emergency such as a collision, by inflating (or extending) the air bag with pressure of gas injected from a gas generator called an "inflator".
FIG. 10 shows an example of an air bag device for a driver of the prior art. An inflator 14 has a leading end fitted in a central opening (or inflator mounting hole) 12 which is formed in a main plate 10a of a retainer 10.
An air bag 16 is formed with a receiving hole 18 for receiving a leading end of the inflator 14. The receiving hole 18 is arranged around a peripheral edge of the mounting hole 12. The receiving hole 18 of the air bag has a peripheral edge held on the peripheral edge of the mounting hole 12 by a holding ring (or patch) 20.
The air bag 16 and the inflator 14 are fixed on the retainer 10 by fixing stud bolts 38 on the holding ring 20, by inserting the stud bolts 38 into bolt holes of the air bag 16, bolt holes of the retainer 10 and bolt holes formed in a flange of the inflator 14, and by fastening nuts 40 therewith.
The air bag 16 is folded in an extensible state and covered with a module cover 22. The module cover 22 is torn by pressure of inflation of the air bag 16 when the air bag 16 is extended by gas injected from the inflator 14.
The driver's air bag device is preferable for protecting the driver if it could extend the air bag 16 quickly at first in the vertical direction and then in the horizontal direction in front of the driver when the inflator 14 is activated.